Fermi detects super solar flare

The solar flare occurred on 7 March, and was classified as X5.4,
with x-class flares being the most powerful that erupt on the Sun. The flare was the largest ever observed with the Large
Area Telescope (LAT) aboard Fermi, briefly making the Sun the
brightest object in the gamma-ray sky. Not only was the flare
bright, it also lasted for around twenty hours, which surpasses
previous events by at least twelve hours.

"For most of Fermi's four years in orbit, its LAT saw the Sun as
a faint, steady gamma-ray source thanks to the impacts of
high-speed particles called cosmic rays," said Nicola Omodei from
Stanford University. "Now we're beginning to see what the Sun
itself can do."

During the peak of the flare, the energy emitted from the Sun reached
around four billion gigaelectron volts, which is 1,000 times
greater than the Sun's ordinary energy output.

Charged particles are accelerated during a solar flare, which
collide with matter in the Sun's photosphere to produce gamma rays.
Fermi's LAT performs a sweep of the sky every three hours, seeking
out gamma rays that are between 20 megaelectron volts and 300
gigaelectron volts. Fermi also hosts the Gamma-ray Burst Monitor
(GBM), which monitors lower energy events.

A less powerful solar flare was observed by both the LAT and GBM
on 12 June 2010, which yielded some interesting results according
to Michael Briggs at the University of Alabama. "Seeing the rise
and fall of this brief flare in both instruments allowed us to
determine that some of these particles were accelerated to
two-thirds of the speed of light in as little as three
seconds."

"Merged with available theoretical models, Fermi observations will
give us the ability to reconstruct the energies and types of
particles that interact with the Sun during flares, an
understanding that will open up whole new avenues in solar
research," said Gerald Share from the University of Maryland.

Events such as this powerful solar flare will continue to become
more common until the Sun reaches its peak in the current solar
cycle in 2013.

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